[llvm] Add XCOFF object file support in sanitizer coverage tool (PR #179884)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 171287 tests passed
* 3045 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.tools/sancov/XCOFF/xcoff-sancov-symbols.test</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/yaml2obj /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/sancov/XCOFF/xcoff-sancov-symbols.test -o /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/sancov/XCOFF/Output/xcoff-sancov-symbols.test.tmp.o
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/yaml2obj /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/tools/sancov/XCOFF/xcoff-sancov-symbols.test -o /home/gha/actions-runner/_work/llvm-project/llvm-project/build/test/tools/sancov/XCOFF/Output/xcoff-sancov-symbols.test.tmp.o
# .---command stderr------------
# | YAML:23:9: error: unknown key 'SymbolAlignmentLog2'
# |         SymbolAlignmentLog2:    5
# |         ^~~~~~~~~~~~~~~~~~~
# | yaml2obj: error: failed to parse YAML input: Invalid argument
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/179884